Rob & K-Stew get in hot water when they swear on set!

Mackenzie Foy – who plays Renesmee, Robert Pattinson and Kristen Stewart‘s child in the upcoming The Twilight Saga: Breaking Dawn, Part 2 – is making bank from the film — mostly from her potty-mouthed costars!

“She’s got a lot of money out of us swearing around her,” he said. “I do it by accident, and especially Kristen does it by accident, because she’ll apologize with a swear… She’s like, ‘Oh sh–! Ugh!’ She can’t stop doing it for about 15 minutes, and [Mackenzie] just waits there [with her hand out].”

The effort by Rob, 24, and Kristen, 21, to curb their profanity come from their respect for the young actress.